The present invention generally relates to antennas, and more particularly, to an ultra-broadband antenna that is incorporated into a garment that may be worn around a human torso.
Most antennas of hand-held radios used by soldiers for tactical operations are monopoles or dipoles that extend from-a radio carried by the soldier. Such antennas have many disadvantages. For example, monopole antennas are narrowband and provide efficient operation over only a small frequency range. However, soldiers today have a need to communicate many different types of information which may include global positioning information, voice signals, and technical data. Each type of communication generally requires a separate frequency band. Thus, it may be appreciated that collectively, a soldier needs to have wideband communication capabilities. Monopole antennas do not provide such broadband operating capability. Also, monopole antennas are clumsy and tend to snag on trees, brush and low ceilings. Most importantly, the monopole antennas provide a visible signature that distinguishes the radio operator and any accompanying officer nearby, making them vulnerable to sniper fire. Because disruption of command, communications, and control is a paramount goal of snipers, reduction of the visual signature of an antenna is highly desirable.
Therefore, a need exists for a broadband, man-carried antenna that does not have a readily identifiable visual signature.
The present invention is directed to an ultra-broadband antenna that is incorporated into an electrically nonconductive garment. The antenna includes first and second radio frequency (RF) elements attached to the garment so that a gap exists between them, where the RF elements each form a band when the garment is worn by a wearer. RF and ground feeds are electrically connected to the first and second RF elements, respectively. A shorting strap electrically connected between the first and second RF elements on the anterior side of the garment generally opposite the feeds helps match the antenna impedance to an external device, such as a signal generator. The gap provides a voltage difference between the RF elements when the antenna is energized. Electrically conductive straps that extend over the shoulder regions of the garment are electrically connected between the anterior and dorsal regions of the first RF element. An impedance matching circuit electrically connected between the first RF element and the RF feed may be employed to approximately match the impedance of the antenna with an external device and the wearer to optimize the efficiency of the antenna for a particular operating band. The garment may be a vest or a pull-over type garment suitable for being worn on a human torso.
These and other advantages of the invention will become more apparent upon review of the accompanying drawings and specification, including the claims.